How great is the risk of endometrial cancer for women who take tamoxifen?
In the BCPT, tamoxifen more than doubled a woman’s chances of developing endometrial cancer compared with women of the same age who did not take tamoxifen. The risk of endometrial cancer from tamoxifen was similar to that for postmenopausal women who take estrogen replacement therapy. The increased risk for endometrial cancer was seen mainly in women ages 50 and older who were taking tamoxifen: they had four times the chances of developing endometrial cancer as women of the same age who were not taking tamoxifen. The risk of developing endometrial cancer in women 50 and older on the BCPT was equivalent to 30 cases of endometrial cancer per 10,000 women per year in the women assigned to take tamoxifen compared to 8 cases per 10,000 women per year in the women assigned to take the placebo. Women taking tamoxifen should be closely monitored by their health care provider for possible signs or symptoms of endometrial cancer, especially abnormal vaginal bleeding. Women who have had a hystere
